a) Field of the Invention
This invention relates to storage holders for optical fibers.
b) Relevant Prior Art
Storage holders for optical fibers have been developed during the recent past for use within the telecommunications industry. These holders have storage chambers for accommodating storage windings of superfluous lengths of fiber which are being directed either to optical fiber connectors or to optical fiber splices. Such holders are stored normally in a particular orientation. In this orientation, the holders, which are tray-shaped, are disposed horizontally and are open at the top for insertion of the fibers as windings into the storage chambers. The holders may have tops to close the trays and may also have fingers extending partly across the storage chambers to define gaps for insertion or removal of fibers. Because the holders are open at their tops, the fiber windings, while being held at their desired radii and configurations upon bases of the holders, are not inclined to move upwards through the gaps and out from the storage chambers. Hence, no problem is found in controlling a fiber in its windings and the fiber may be removed manually by unwinding it from a storage chamber through the gaps. Absolute fiber control is thus guaranteed.
It is now being suggested that optical fiber cable should be used in an outside plant uncontrolled environment to transmit multimedia transmission signals (broadband services and cable television signals) to the home or other buildings. Indeed, some systems have been developed and are in use. These systems incorporate optical fiber storage holders having design concepts similar to those used in telecommunication optical fiber systems. However, the use requirements are different for holders to be used to transmit broadband data and cable television signals in the outside plant environment from those for telecommunications systems in the inside plant environment and as a result, known holders are not particularly successful in retaining optical fibers in the bases of the storage chambers. A reason for this is that when such holders are used for the purpose of transmitting multimedia signals or cable television signals, the holders are necessarily carried in an outside plant environment within weatherproofed containers provided for the conversion of optical fiber signal reception into electrical signals. These containers are mounted in various positions, either upon telephone poles, slung beneath carrier cables extending between the poles, above ground in pedestal housings or below ground in hand holes. Movement of the containers under ground vibrations, wind conditions, accessing other components and also temperature change conditions effect deformation of the fiber storage holders. Unlikely as it may seem, under such conditions, the fibers in the windings in the storage chambers are found to move out from the chambers, presumably through the insertion and removal gaps provided. Hence, it follows that when a maintenance engineer opens the containers with the object of opening the holders for inspection or maintenance procedure, he may discover that the stored lengths of fibers are falling out from the chambers and are difficult in these circumstances to be correctly placed back into storage positions without causing possible fiber damage and thus customer interruptions. This problem is aggravated because the maintenance person is operating high above ground level or below ground level and is possibly operating in difficult weather conditions. Also under vibrations conditions fibers moving outwards can get pinched between lid or cover and storage chamber causing fiber breakage and thus customer interruptions.